Diagnostic Considerations

The current Centers for Disease Control and Prevention (CDC) guidelines for diagnosis of an arbovirus infection require the presence of an acute febrile illness with encephalitis during a time when viral transmission is likely and at least 1 of the following criteria is met:

Immunoglobulin M (IgM) positive to the organism in the CSF; presumptive positives can be made from the remaining biochemical assays (eg, hemoagglutinin inhibition, immunofluorescence, neutralization, complement fixation)